1. Field of the Invention
The present invention relates to a long sandwich molded article such as a side molding for an automobile which has excellent attractiveness after mounting, dimensional stability, etc. In particular, it relates to materials constituting the long sandwich molded article.
2. Description of the Related Art
A side molding used as the trim or exterior parts of an automobile, a ship or the like needs to fulfill many requirements. It must be attractive after mounting. It also needs dimensional stability during its use, and also to have excellent scratch resistance and product attachability.
The above term "excellent attractiveness after mounting" means that the side moldings can be affixed to the door of an automobile, or the like, leaving no space between door and molding, or that the distance between the side moldings which have been affixed is a predetermined distance.
The term "excellent dimensional stability" means that at the time of use, the side molding is not greatly expanded or contracted, for example, by the difference between temperatures in winter and summer, or daytime and nighttime.
The term "excellent scratch resistance" means that the surface of the side molding is scratch resistant during mounting or at the time of use.
The term "excellent product attachability" means that for example, in an assembly line of an automobile, the side molding can easily be attached to the automobile. For example, when the side molding is warped, it should be affixed while actively pressing it in accordance with the surface shape of a material to which the side molding is to be affixed. When the side molding is either too flexible or too stiff, it is difficult to stick. Therefore, the product attachability is poor.
For example, polypropylene resins have been used in long molded articles such as side moldings as shown for example in Japanese Patent Application Kokai Nos. 63-95252 and 61-233048. However, no one has even disclosed a long molded article which satisfies the above four requirements.
Particularly in recent years, there has been a growing demand for excellent attractiveness after mounting and dimensional stability. A reduction of the coefficient of linear expansion of the material used for the long molded article has been used to satisfy this demand. Proposed means for effecting the reduction have included blending of a fibrous filler such as glass fiber with a conventional material such as polypropylene resin as in Japanese Patent Application Kokai No. 61-34047 and Japanese Patent Application Kokoku No. 1-22299.
However, when the fibrous filler is thus blended, a long molded article obtained from the blend may have appearance defects such as warping or twist. Therefore, the attractiveness after mounting and product attachability are deteriorated.
Others have proposed using a thermoplastic elastomer having a high impact resilience as a material satisfying the demand for high scratch resistance. The thermoplastic elastomer, however, has a large coefficient of linear expansion. When used, the above-mentioned attractiveness after mounting and dimensional stability have not been satisfactory. Moreover, the whole article obtained from the thermoplastic elastomer is too flexible, and hence the product attachability is deteriorated.
In consideration of such problems with conventional moldings, the present invention was made for obtaining a long sandwich molded article which is excellent particularly in attractiveness after mounting and dimensional stability and is excellent also in scratch resistance and product attachability.